How to Pressure Wash Car Engine Bay: Power Wash Car Engine Without Screwing It Up in 5 Easy Steps

By Power Tools

September 12, 2019

I know, we all know, everyone washes their cars. Someone must be out of their mind not to do so.pressure wash car engine

But, did you ever thought of engine cleaning in the first place? This is like taking a bath without brushing your teeth!

Grease, dirt and oily build-up leave black coated filth on the engine. I suggest to pressure wash car engine bay, which is an effective way of cleaning those grimes.

Taking care from the outside leaves shine for others but under the hood, the engine can be in a terrible situation. Using a pressure washer to wash your car might be the step for keeping the engine in good operating condition.

But, make sure you do the right way. Let’s see how it’s done the right way.

Is Power Washing Bad for My Car? (What the Manuals Say)

When my neighbors first saw me washing my car engine, they were like, OMG!

Never thought (they) that was a good idea. And kept asking me is it good or bad?

I don’t blame them that they do not know the right way of cleaning. Most of the car manuals do not cover this topic. But some says it can be washed after heavy slug with care.

Even shaving your beard has a wrong and right way. The wrong way of shaving is going to cost you pain. Problems after power washing would never appear if you do it the right way. Otherwise, pressure washing car engine is safe and sound.

The Wrong and Right Way of Pressure Washing Engine

Why you should even bother for this? Isn’t pressure washing is super easy?

Yes. But every process has the right and wrong way to perform. Pressure washing is a safe process until you choose the wrong way.

So, what are the ways all about?

  • The wrong way includes a heavy-duty 3000 psi pressure washer, 0° blast nozzle tip. This combination is going to wreck the hell out of your car engine.
  • The right way of cleaning is using a 40° nozzle tip combining with a moderate psi electric or gas pressure washer, gently spraying water keeping the lance distance of at least 3 feet.

The right way ensures a properly cleaned car engine that looks stunning.

Engine Components to be Protected

The right way is the safe way. This way your engine components can be safe.

But, in this process, there is a key player-Water. Water jets are vulnerable to electrical components. Even worn bolts can be washed away by the force.IP rating for pressure washer

To better protect your electrical parts you have to understand exactly which components you need to get covered with a plastic bag.

For this first, you need to understand the IP rating. Then check the IP rating of your car’s electrical components and enclosures at the engine area. If there is not mentioned, assume it as less than IP5.

Any rating that is below IP 5, must be covered up with poly bags.

Refer to the image to understand the IP rating in detail.


Let me make it easier for you if you are still confused which parts to cover with wrapping polybag. In most of the cases, these components need to be wrapped for protection.

  • Alarm system
  • Loose electrical connection
  • Battery wiring
  • Distributor
  • Alternator

Engine Cleaning With Engine Degreaser: Speed Up the Process

Although the buildup on the engine block is not grease, unless you actually put it there, but the slug appears as sticky as grease. And dust mixed up with the slug makes it way too difficult to wash with only water. No matter how much pressure you put.

We don’t even wash our oily hand with only water.

To make the job easier and effective using a chemical to wash loosen or remove the greasy build up is a wise move.

By using the term chemical I mean detergent or ready to use degreaser spray.

First, you need to identify the exact condition of your engine bay.

Is it Too Greasy and Oily Stained Engine?

For this situation, a normal/soft degreaser is not going to work effectively. You need a degreaser that is heavy duty.

Simple Green manufactures a degreaser for this purpose. This one is extremely effective with grease build up.


As it comes in concentrated form, you can easily dilute it to the desired level for proper degreasing. Also, this is not harmful to plants or landscape. Paying some extra effort for this kind of heavy grime is worth a shot.

Use it on the pressure washer detergent tank with proper dilution ratio and use a scrub to make way for a degreaser.

Is it Dusty but Not That Oily?

So, this might be when you washed your car engine not long before. Only dust build-up is not a mess.

For this condition, you can directly spray degreaser in proper dilution. Scrub the engine for dust free look.

Chemical Guys make a great product for this purpose. This is super easy to spray directly. 1 cap degreaser and water will fill a standard size spray bottle.


After spraying it on you can leave it for pressure washing or wipe it with a towel that you will never use on paint.

This Chemical Guys signature series degreaser is awesome in its purpose. This is also great for tires and rims.

Choose the Right Pressure Washer

Here’s the most important part. Getting a pressure washer.

You do not need an industrial grade pressure washer. If you have a pressure washer with which you wash your car, is just great. If you don’t, read our recommendation of the best pressure washer for a car.

I recommend, having a pressure washer within the range of 2000 psi to 2200 psi. This range is safe. If you plan to buy a 3000 psi washer, then go for a pressure washer with easy control of psi.

Furthermore, use a 25° nozzle to start with.

That nozzle is going to fit with your spray gun or trigger gun whichever you use.

A Video Of Car Engine Bay Cleaning

Steps for Cleaning Car Engine Bay with Pressure Washer without Damage

1. Manage Everything You Need Before Starting

Gather everything that will be needed while pressure washing. You do not want to run and pick each thing while pressure washing.

  • Plastic bag and tape to protect electrical components
  • Degreaser and detergents needed
  • Pressure washer
  • Scrubber
  • Brush
  • Pressure washer nozzle

2. Focus on Precautions

  1. Make sure to use a chemical which is non-corrosive
  2. The engine must be cooled down before spraying chemical or water
  3. Cover necessary electrical components with wrapping polybag and tape them

3. Apply Degreaser

Before pressure washing spray the degreaser on the engine block. This will help loosen the grime for pressure washing.

Use a scrubber to scrub the grime or grease to loosen up. Apply the degreaser especially to those places where reaching is tough.

4. Pressure Wash Car Engine

Now, this is the time for pressure washing. Start with a 25° nozzle and if required, switch to a 40° nozzle. Always stand back from the engine keeping a distance of three feet.

Pressure washing from a close range can damage engine parts.

5. Remove Plastic Bag and Dry the Engine

Use a dryer to dry engine faster. Or just let dry. You can use a microfiber towel to rinse off the water and dry it. Remove the plastic bags that were wrapped to protect electrical equipment.

Cleaning car engine with a pressure washer is the easiest way. But always remember to keep a safe distance and cover the electrical equipment to make the job safer.